1. Field of the Invention
The present invention relates to an exposure control method and a device therefor for use in a photographic camera, a motion picture camera, a television camera or the like, and more particularly to a method of controlling exposure for such an optical instrument in which the exposure is controlled based on the brightness of a focused image of the object to be photographed and an exposure control device for carrying out the method.
2. Description of the Prior Art
There have been known an average light measuring system in which one or two light measuring elements are used for measuring the brightness of the image of an object as a whole and a central spot light measuring system in which the central portion of the image is particularly measured. Further, recently it has been known to use a number of light measuring elements to measure the various portions of the image and detect the maximum and minimum brightness of the image to control exposure based on the maximum or minimum brightness or average brightness calculated therefrom.
The above-mentioned conventional methods of exposure control suffer from defects in that the obtained exposure becomes under or over depending upon the specific brightness distribution of the image as of back-light image or scene having a dark background.